2 Kbit I2C EEPROM for parameter storage
The Microchip 24AA02T-I/SN is a 2Kbit serial EEPROM with an I2C interface running at 400 kHz. It stores 256 x 8 bits of non-volatile data, organized for byte-level reads and writes. The 900 ns access time is fast enough for most microcontroller parameter-retrieval loops, and the 5 ms write cycle per word or page sets the timing budget for firmware update routines. The supply range spans 1.7V to 5.5V, which lets this part drop into both 1.8V and 3.3V logic domains without a level translator.
Wide supply — the deciding spec
The 1.7V minimum supply is the main reason to pick the 24AA02T-I/SN over the 24LC025T-I/ST, which requires 2.5V minimum. In a 1.8V-only system — battery-powered IoT nodes, single-cell Li-ion designs — the 24AA02T-I/SN runs directly off the rail. The 24LC025T-I/ST needs a boost converter or a second regulator, adding cost and board area.